feat(api): R3-A recipe engine — search, tags, family scope, recommendations

- GET /api/recipes: added cuisine, protein, dietary, ingredient, max_time,
  spice_max, calorie_max query params
- GET /api/recipes?family_profile_id=… hides never-suggest blocklist recipes
- GET /api/recipes/recommended: returns feedback-driven recipe suggestions
- Update docs: remove completed open items from planner-algorithm.md

.gitignore

@@ -147,6 +147,9 @@ nginx/ssl/*.pem
 # Node
 node_modules/
 
+# Local data dumps
+mealplanner_postgres_data.tar.gz
+
 # R2-B email console outbox (local-only spike artifact)
 backend/var/